(Reuters) - Otto Habsburg-Lothringen, the eldest son of the last Austrian emperor, died at his home in Germany on Monday.
Here are some facts about Otto and his family:
* Archduke Otto von Habsburg, born in November 1912, became head of the imperial House of Habsburg on the death of his father in 1922.
* Otto's parents were Archduke Charles -- later Emperor Karl I of Austria, king of Hungary, Bohemia, Croatia etc. -- and Princess Zita de Bourbon-Parma (later empress and queen). From 1916 on, Otto was the crown prince of Austria-Hungary.
-- Charles had become heir-presumptive with the assassination of Archduke Franz Ferdinand, his uncle, in Sarajevo in 1914, the event that precipitated World War One. Charles's reign did not begin until 1916, when his grand-uncle, Franz Josef I of Austria died.
* Forced into exile in 1918 to Switzerland and Madeira, Otto graduated from the University of Leuven, Belgium, in social and political science in 1935.
-- He was already an early promoter of European unity and joined the Paneuropa Union in 1936.
* During the 1930s, he openly objected to growing Nazism in Germany and opposed in March 1938 the German annexation of Austria. The Nazis issued an arrest warrant for him.
* At the outbreak of the war, he had helped more than 10,000 people, mainly Jews, to escape.
* He spent most of the war years in the United States, where he worked to restore Austria to democratic rule.
* He became a member of the European Parliament at its first direct election in 1979. He remained a member for 20 years.
* He made history when he undertook the first Pan-European picnic on August 19, 1989, at Sopron on the Austro-Hungarian border, the occasion on which the Iron Curtain was lifted for the first time.
* The name Habsburg is derived from the castle of Habsburg, or Habichtsburg ("Hawk's Castle"), built in 1020.
* The Habsburgs became the ruling family of the Austro-Hungarian empire, stretching from Austria in the west to present-day Romania in the east.
* World War One led finally to the end of the Habsburg Empire. While Czechs, Slovaks, Poles, Romanians, Serbs, Croats, Slovenes, and Italians were all claiming their share of the spoils, nothing remained to Charles, Otto's father.
-- In November 1918, Charles issued proclamations recognizing Austria and Hungary's right to determine the future form of the state and renouncing for himself any share in affairs of state. But he did not abdicate his hereditary titles either for himself or for the Habsburg dynasty.
-- The national assembly of the Austrian Republic passed the "Habsburg Law" of April 3, 1919, banishing all Habsburgs from Austrian territory unless they renounced all dynastic pretensions and accepted the status of private citizens.
-- Otto was not granted a visa to return to Austria until June 1966 after the People's Party won a majority in a general election. Under former Chancellor Bruno Kreisky, tensions between Austria and the Habsburgs eased, although some family members continued to demand the restitution of Habsburg assets.